A Divergent Alkyne Diol Directs [2 + 2] Photoreactivity in the Solid State: Cocrystal, Supramolecular Catalysis, and Sublimation Effects

Abstract

2-butyne-1,4-diol (1,4-bd) is used as a divergent ditopic template that directs trans-1,2-bis (n-pyridyl) ethylene (n,n'-bpe, where n = n' = 3 or 4) to undergo an intermolecular [2 + 2] photodimerization in the solid state. The components of cocrystals [(1,4-bd)·(4,4'-bpe)]n and [(1,4-bd)·(3,3'-bpe)]n form 1D hydrogen-bonded polymers with n,n'-bpe assembled as infinite parallel stacks. The alkenes undergo [2 + 2] photocycloadditions to form rctt-tetrakis (n-pyridyl) cyclobutane (where n = 3 or 4). We demonstrate that the reactive solid involving 4,4'-bpe exhibits supramolecular catalysis.